1. Field of the Invention
The present invention relates to an inspecting apparatus for a foreign matter (impurities) for detecting a foreign matter got entered a liquid product (including a fluid product), such as drinks and liquid drugs, and more particularly to an inspecting apparatus for a foreign matter achieving high-speed and highly accurate inspection by providing a conical prism at imaging means end at the time of inspection, so that a shape at the bottom portion of a container where a foreign matter is most likely to deposit is magnified while at the same time an entire area subject to inspection is pictured.
2. Description of the Related Art
Adoption of the HACCP (Hazard Analysis Critical Control Point) system to the Food Sanitation Law and enforcement of the PL (Product Liability) Law in recent years have been making it mandatory to further ensure the product safety by forestalling a hazard, such as microbial contamination and entrance of foreign matters like metal, fabrics, hair, etc., that could occur in any stage from manufacturing/processing of products, such as food and drugs, to consumption by end consumers through storage/distribution of the products.
HACCP is a hazard analysis and critical control point system established in the United States and is highly evaluated across the world as a sanitary control system method. The HACCP system is a science-based sanitary control system in which product safety is addressed throughout the manufacturing procedure so that preventive measures in the manufacturing procedure are emphasized in contrast to a conventional sanitary control system in which inspection of final products is emphasized. The HACCP system includes two sections: hazard analysis (HA) and critical control point (CCP), and it further ensures the product safety by forestalling an occurrence of a hazard in the manufacturing procedure without overlooking any possibility by (1) checking/analyzing a hazard, such as microbial contamination, that could occur in any stage from manufacturing/processing of food to consumption by end consumers through storage/distribution of the products and setting critical control points to prevent the hazard, (2) setting the criteria of control and constantly monitoring whether the critical limit is being met by checking the records of control, and (3) managing and controlling hazards of other natures with a pre-requisite program (PP).
In a mass-production line of a manufacturing factory, workers detect foreign matters got entered liquids filled in containers by visual inspection. However, such visual inspection is conducted on spot-check basis that one in every certain number of containers is picked up and inspected. Hence, there is a problem that it is by no means reliable inspection conducted for each individual product.
In the case of a method on one hundred percent inspection basis by deploying inspectors along the production line, relatively large foreign matters can be detected by the visual inspection, but minute foreign matters cannot be detected, which raises a problem that the detection is less accurate. Also, the ability of the visual inspection of the inspectors is no longer comparable to an increasing speed of the production line, and it is true that the inspection efficiency is becoming poor. Further, the visual inspection has no effect on colored liquids, such as coffee or cola, and there has been a need for a countermeasure.
As an inspecting method for a foreign matter got entered a liquid solution filled in a container other than the visual inspection, the container may be pictured from the outside by an inspection camera, so that the presence or absence of non-conformity is detected based on image information thus obtained. However, in order to allow the containers of the liquid product to stand upright firmly, the concavity at the bottom portion is deepened from the center to the outside, and a foreign matter in the liquid is most likely to deposit at the deepest concaved bottom portion. Hence, it is effective to picture chiefly such a portion at the time of inspection. FIGS. 1A and 1B and FIGS. 2A and 2B show the foregoing state. FIG. 1A is a side view showing the bottom portion of a PET bottle 100 with a foreign matter 101 deposited on the bottom portion, and FIG. 1B is a bottom view thereof. FIG. 2A is a side view showing the bottom portion of a PET bottle 102 with a foreign matter 103 deposited on the bottom portion, and FIG. 2B is a bottom view thereof.
As a method for magnifying an image of an arbitrary portion, a zoom mechanism or the like may be provided to the optical system to picture an image. However, when the zoom mechanism magnifies a specified portion, it also magnifies the entire object being inspected at the same magnification. Thus, there is a portion that goes out the range of the optical system installed to match with the actual size of the object being inspected. This makes it impossible to inspect the entire area subject to inspection, thereby raising a problem that the reliability is lowered.
FIG. 3 is a view showing an example of an optical detecting apparatus, in which a PET bottle 111 as an object being inspected is irradiated by a light source 110 so that transmitted light from the bottom portion of the PET bottle 111 is received by a CCD sensor 120, and a light reception signal from the CCD sensor 120 is subjected to image processing by a data processing apparatus (not shown), whereby a foreign matter 113 got entered a liquid product 112 inside the PET bottle 111 and deposited at the bottom thereof is detected.
According to the inspecting apparatus arranged as above, in order to utilize the optical system effectively, the detection is conducted by matching the maximum diameter of the PET bottle 111 with a full size 130 of the optical system as shown in FIG. 4. In other words, because the foreign matter 113 needs to be magnified as large as possible for the detection, the maximum diameter of the PET bottle 111 is set to the full size 130 of the optical system. Hence, the size of the detected foreign matter on the image depends on the magnification of the optical system defined by the full size 130. The accuracy of inspection is improved by detecting the foreign matter at the larger magnification. Thus, when the foreign matter is magnified for the detection, only the image has to be enlarged by providing a zoom mechanism to the optical system. However, as shown in FIG. 5, the zoom mechanism also magnifies the entire pictured region at the same magnification (characteristic A of FIG. 17), and the entire object being inspected does not come within the range of the optical system. A portion 111A indicated by a broken line of FIG. 5 shows a portion that goes out from the range of the optical system. Hence, there may be a case that a region where a foreign matter is present goes out from an inspection screen. This raises a problem that a foreign matter cannot be detected in a reliable manner.
A method of magnifying an arbitrary portion by editing a pictured image with software may be proposed. However, because an inspection time per container is too long, this method is not suitable for use in a high-speed mass-production line for the drinks or liquid drugs, thereby raising a problem that the manufacturing yield is lowered.
Additionally, the conventional inspecting apparatus is not able to detect a foreign matter by an optical method or irradiation of laser beams when a colored translucent PET bottle or bottle is filled with a transparent liquid, or when a transparent PET bottle or bottle is filled with a colored liquid, such as coffee, juice or cola. A foreign matter may be detected with X-rays when the container is opaque or translucent. However, the X-rays per se have ill effects on the human body; moreover, a large-scale and fairly expensive apparatus needs to be installed.
For this reason, the inspection of a bottle or a PET bottle for a foreign matter has not been conducted at all once a colored liquid product is filled therein. However, in order to attain the perfection of the product, there has been a need to conduct the inspection of bottles or PET bottles for the foreign matters in a reliable manner whether the liquids are transparent or colored.
The present invention is devised in view of the foregoing, and has an object to provide an inspecting apparatus for a foreign matter for use in a production line for manufacturing liquid products, such as drinks and liquid drugs, which can detect in a reliable manner whether a foreign matter has entered a liquid inside a container, such as a bottle and a PET bottle, and a foreign matter in a colored bottle or PET bottle or in a colored liquid as well.
The present invention relates to an inspecting apparatus for detecting if foreign matter entered an object that contains a liquid being inspected optically with imaging means, and the object of the present invention is achieved by disposing a conical prism between the object being inspected and the imaging means.
The object of the present invention is achieved more effectively by arranging in such a manner that: the conical prism is a single-side conical prism; the conical prism is a double-side conical prism; the imaging means is a CCD sensor; the liquid product and the object being inspected are transparent, and the foreign matter is one of a suspended foreign matter and a deposited foreign matter; or the object being inspected is one of a bottle and a PET bottle.
The present invention relates to an inspecting apparatus for detecting foreign matter entered an object that contains a liquid being inspected optically with imaging means, and the object of the present invention is achieved by arranging in such a manner that light radiated through to the object being inspected is an infrared light having a wavelength of 750 to 1000 nm; and a conical prism is disposed between the object being inspected and the imaging means.
The object of the present invention is achieved more effectively by arranging in such a manner that: the infrared light is irradiated at power in a range from 0.7 mW to 100 W both inclusive; the conical prism is a single-side conical prism; the conical prism is a double-side conical prism; the imaging means is a CCD sensor; one or both of the liquid product and the object being inspected are colored, opaque, or translucent; or the object being inspected is one of a bottle and a PET bottle.